It is known to apply liquid dyes to moving substrates, particularly textile materials, from a plurality of streams which are directed onto such materials and selectively controlled to produce a pattern thereon. It is also known, in connection with such methods and apparatus, to use a control fluid, commonly air, as the means by which flow of liquid dye is controlled. While various techniques for control have been used, the control fluid methods commonly employ one of the following approaches.
In a first approach (see e.g., U.S. Pat. Nos. 3.985,006, 3,969,779 and 4,095,444), a stream of marking material is directed at the desired substrate and a transverse stream of a control fluid is used to divert the marking material stream into a barrier or the like, in response to externally supplied dyeing pattern information.
In a second approach (see e.g., U.S. Pat. Nos. 3,443,878 and 3,570,275), a curtain of marking material is directed in closely spaced, parallel relation to the desired substrate, and one or more streams of a control fluid are directed through the curtain in the direction of the substrate, thereby causing displacement of marking material from the curtain onto the substrate.
In a third approach (see e.g., U.S. Pat. No. 4,501,038), a stream of a control fluid such as air is directed into a mixing chamber in which a quantity of marking material is introduced in accordance with pattern information. The chamber may be positioned in close proximity to the desired substrate, and may be configured so that, for example, air enters the chamber from the top, intersects a flow of marking material entering the chamber from the side, and causes a spray of air and marking material to exit from the confines of the chamber, via a conduit extending from the bottom of the chamber, onto the desired substrate.
Although these apparatus have shown limited utility for the production of products with fairly regular dyeing patterns, they have proven inadequate to produce more "complex" patterned products of two basic categories. The first may be called a "diffuse pattern" product, in which the desired substrate has been marked or dyed in a pattern which exhibits soft, diffused color boundaries and perhaps exhibits color areas which overlap and blend almost imperceptibly from one to another, and which product may exhibit literally dozens or hundreds of different colors, shades, or hues over the pattern area. The second category may be called a "random pattern" product, in which the distribution of color within areas on the substrate has a random or pseudo random appearance. The color may be in the form of extremely small flecks or specks, or may be in the form of larger areas having irregular, random appearing borders. Some products exhibit characteristics which are a combination of these two categories, wherein, for example, irregularly shaped patches of color exhibit diffused boundaries and contain a multitude of varying shades or hues, and which may contain randomly distributed and/or overlapping specks of color in localized areas of the substrate.
Coassigned U.S. Pat. No. 4,923,743, entitled Apparatus and Method for Spraying Moving Substrates, discloses a unique apparatus that will produce such "complex" patterned products. Therein several arrays of closely spaced streams of marking material are normally directed into corresponding collection surfaces or receptacles. Each stream in a given array has associated with it a source of pressurized air or other control fluid which, on command, forms and directs an atomizing control fluid stream into contact with the marking material whereby the stream of marking material is transformed into a mist of variously sized diverging droplets which are propelled in the direction of the substrate to be marked. By interrupting the streams of atomizing fluid in oscillatory fashion, uniform reproduction of various solid color or multi-hued patterns is possible. By employing such controlled pulsations, the marking material sources, directing fluid sources, substrate, droplet size distribution and the degree of droplet dispersion can be carefully controlled, yielding intricate patterns possessing great subtlety, delicacy, and variety which may be produced with a high degree of reproducibility. By providing for the nonsimultaneous actuation of adjacent atomizing fluid streams along a given array, a wide variety of side to side or fill direction patterns may be produced.
In prior art apparatus, the conduits and orifices for delivery of the marking material have been fashioned separately from the conduits and orifices for delivery of the air (control fluid) stream. The separate components were then assembled in the desired configuration by mounting them in a holder along with other pairs of separate components to form an array of marking material/control fluid orifice combinations. For the machine to operate optimally, each orifice combination in the array must deliver exactly the same amount of marking material onto the substrate as its neighbor over the entire width of the substrate. Due to manufacturing tolerances in the conduits, orifices and the holder, the resulting tolerance build up of the components over the entire array was large enough to effect a variation in the geometry of the assembled components. This variation in geometry adversely affected the flow rate of the marking material and control fluid, the directivity of the marking fluid and control fluid, and the amount of aspiration induced pressure drop seen across marking material orifices. This in turn could produce a variation in marking material flow onto the substrate target area, creating streaks on the substrate.
The individual dye nozzles can be retracted from the air stream to eliminate aspiration, and the various components are or can be arranged for manual alignment. However, such an arrangement has proved to be labor intensive because of the number of component combinations involved (sometimes as many as 573 or 2000 combinations per machine) and the trial and error nature of the adjustments. Such an alignment procedure is not efficient or economical in the production environment. Additionally, because of the long length of the marking material conduit and because the conduit had a single exit orifice, a solid contaminant, once in the conduit would clog the orifice and would be difficult to remove.
The invention described herein provides a mechanism whereby the geometry of the air and dye conduits and orifices is maintained to minimize or eliminate variation in dye flow rate and directivity to the substrate without the need to employ complex and inefficient alignment procedures. With this mechanism aspiration of dye is permanently eliminated from the process and whereby solid contaminants can be more easily removed from the marking material conduit. Other features are set out in the Summary of Invention below.